Nantong Xinbang Chemical Co., Ltd. as a manufacturer of coated sand lubricants, this article uses calcium stearate as an example to introduce the application of calcium stearate in coated sand. The quality requirement for calcium stearate is GB: HG/ T2424-2012.

The coated sand lubricant is usually calcium stearate, which has an influence on the fluidity, caking, gas generation, strength and thermal toughness of the coated sand. Calcium stearate is evenly distributed in the coated sand. At the temperature of the core, the resin and calcium stearate are softened and melted, forming interpenetrating networks, increasing the flexibility of the resin, increasing the flexibility of the shell, and resulting in heat. Increased toughness. The lubricating properties of calcium stearate improve the fluidity of the coated sand and increase the compactness of the sand core, thereby increasing the strength of the core. The melting point of calcium stearate is 60-80 degrees higher than that of resin. After heating, the calcium stearate is softened much later than the resin. The unmelted calcium stearate dispersed in the sand plays a role in the skeleton in a certain range. The sedimentation of the sand grains is blocked during softening, and the formation and expansion tendency of the sand core voids are reduced. At the same time can also play a role in improving the melting point of the coated sand. Calcium stearate can also improve the thermal cracking resistance of coated sand. The main cause of thermal cracking of coated sand is thermal expansion and thermal stress. With the increase of calcium stearate, thermal cracking time is gradually delayed. Since calcium stearate has a higher melting point than the resin, its increase is beneficial to increase the thermoplasticity of the sand core, thereby relaxing the thermal stress of the sand core. Although the amount of calcium stearate is small in the coated sand, the effect is very large, which can prevent the caking of the coated sand, improve the fluidity, and improve the resistance to shelling and mold release. The quality of calcium stearate will not only affect the strength of the coated sand, but also the high temperature performance of the coated sand. Adding a certain amount of silica to the calcium stearate synthesis can increase the high temperature performance of the calcium stearate in the coated sand to a greater extent. To improve the performance of the coated sand, some brick additions are added.

Calcium stearate as a lubricant has been widely recognized for its role in improving the normal temperature strength and fluidity of coated sands. In a certain range, the more calcium stearate is added, the higher the melting point of the coated sand is, the smaller the sedimentation rate is, and the smaller the sand core voids; in the same amount, the higher the melting point of calcium stearate is, the more obvious the effect is. The effect is good. The undissolved calcium stearate dispersed in the sand plays a role in the skeleton within a certain range, hinders the sedimentation of the sand during softening of the resin, and reduces the tendency of the sand core to form and expand.